Patient-Reported Symptom-to-Diagnosis Interval and Documented Prior Eczema/Dermatitis Diagnosis in Relation to Dermal Invasion in Extramammary Paget Disease: A Retrospective Cohort Study

BACKGROUND: Extramammary Paget disease (EMPD) frequently mimics chronic eczema/dermatitis, contributing to delayed diagnosis. Although dermal invasion is prognostically important, it remains unclear whether diagnostic-timeline measures are associated with invasion at diagnosis. OBJECTIVES: To estimate the associations of the patient-reported symptom-to-diagnosis interval and a documented prior eczema/dermatitis diagnosis with the presence of dermal invasion at EMPD diagnosis. METHODS: We reviewed patients with histologically confirmed EMPD at a tertiary center (May 2006-August 2025). Symptom-to-diagnosis interval was patient-reported; prior eczema/dermatitis was confirmed by external records or referral letters. Invasion used maximum depth in definitive surgical specimens. Primary logistic regression adjusted for age and sex; Firth sensitivity analysis also included involved-subunit count. Adjusted ORs were 1.01 (95% CI 0.88-1.16) per 12 months and 1.13 (0.35-3.60) for prior eczema/dermatitis. Firth estimates remained null after subunit-count adjustment (0.98 [0.88-1.13] and 1.23 [0.39-3.81], respectively); subunit count was associated with invasion (penalized OR 1.55 [1.02-2.45]). CONCLUSIONS: Neither measure showed a detectable association, but the small noninvasive group and wide confidence intervals leave meaningful effects unresolved. Referral-enriched case mix limits generalizability; a short interval does not exclude invasion.